One thing I hate about my D1 is that it weights about a ton. It is SOOO big that it actually gets in the way. Hard to even carry. I was planning to move up to a D1x but I want to see the D100. Seriously, what difference can there be between the two cameras besides their size? OK, if I was in Afghanistan maybe I would insist on the D1x. But realistically, I rarely shoot professionally (some portrait work now and then). A smaller lighter camera would be more my style.
And truthfully, the D1 has so many esoteric features, I always carry the camera manual with me. Even after two years I still do not remember what all the various switches and knobs do, let alone all the custom setting in the back window! (Oh that's right, custom setting 7 needs to be set to 1 so that the auto exposure locks when the shutter button is pressed half way down - otherwise you have to press the AE-L/AF-L button) Wow that's easy to remember --NOT!